Conductive Gel for use with Pain Doctor, Circulation Maxx, Circulation Pro or any TENS machine can also be used for TENS & EMS electrodes to improve conductivity for best stimulation & results. The clear gel can also be used to attach electrodes when they have lost their self adhesive properties. 100ml. Help get the most out of your electrical pain relief device by applying the gel directly to the area to be treated by your TENs or EMS device.